Electroluminescent polymer structure
One type of electroluminescence polymer that include at least one side-chain-tethered polyhedral oligomeric silsesquioxane that will form self-assembled structure and may build a free volume among the polymers to prevent the polymers from stacking and enhance luminescence efficiency and thermal stability.
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1. Field of the Invention
The present invention relates to an electroluminescent (EL) polymer material, particularly to a red luminescent polymer material.
2. DESCRIPTION OF THE RELATED ART
Most of electroluminescent polymers present more efficient injection and transmission of electric holes than ones of electrons due to the existence of abundant π electrons. Thus, in order to enhance the efficiency of a device, the incorporation of electron transmission is necessary. Polyquinoline and its derivatives have been applied to a layer of electron transmission for LED recently because they perform high thermal stability, high anti-oxidation, good mechanical characteristic, a good formation capability. However, poor solubility is disadvantageous for their applications.
The derivatives of fluorene may present specifically physical and chemical characteristics in the presence of rigid and coplanar biphenyl configuration. Next, polyfluorenes functionalized by modifying the C-9 position of the fluorine monomer may provide good solubility without raising steric hindrances among polymer backbones. Furthermore, fluorine exhibits high quantum efficiency and good thermal stability. As a result, the expected blue emission from polyfluorene becomes an attracting material in application. However, the main drawbacks of polyfluorenes (PFs) are the formation of excimer and aggregates during heat or circuit treatment. Moreover, the C-9 position of the fluorine monomer leads to keto defect and further results in luminescence change. Meanwhile, how to modify light color is another issue about studying the derivates of PFs. One of the most recent approaches involves introduction of PFs into green and red luminescent material. Another one of the approaches involves the copolymerization of PFs and monomers with low energy level. For example, the 5 mol % amount of monomers incorporated with PFs may modify light color from blue to yellow and green. Generally, the color of luminescence may be efficiently modified by incorporating monomers with low energy into PFs. So far, besides few reports about blue light modified to red light, most of researches are relevant to yellow and green light. Accordingly, there is still room for improvement and growth about luminescence color, emitting efficiency, mass production, heat resistance and life time. For example, FIG.—1 is a schematic diagram illustrating polymer modification with tethered polyhedral oligomeric silsesquioxane (POSS). Conventionally, POSS 112 is introduced into the main chain 110 of a polymer. Such as a configuration enhances mechanical strength and heat resistance. However, the freedom degree restricted by the presence of POSS 112 on main chain 110 of the polymer may not reduce dielectric constant efficiently.
SUMMARY OF THE INVENTIONIn order to enhance heat resistance of luminescent polymer, one of objects of the present invention provides a luminescent polymer material with inorganic material attached covalently to a side chain on the main chain of a polymer, which may enhance luminescent efficiency, heat stability and resistance.
Another one of objects of the present invention is to provide a red luminescent polymer with porous material in steric hindrance configuration introduced into a side chain, which not only prevents polymer chains from approaching too much and resulting in molecule aggregation but also improves solubility.
Moreover, one of objects of the present invention is to provide polymer nano-composites. Tethered polyhedral oligomeric silsesquioxane is introduced on the main chain of a polymer to enhance quantum efficiency. Accordingly, one embodiment of the present invention is to provide red light luminescent polymer. The main chain of the polymer is associated with inorganic composition on a side chain so as to form self-assembly structure.
FIG.—1 is a schematic diagram illustrating polymer modification with tethered polyhedral oligomeric silsesquioxane (POSS).
Accordingly, special volume enlarges upon increasing free volume between copolymers, which may reduce the dielectric constant of a copolymer with POSS. Moreover, compared with one prior art having POSS at two ends of a main chain, the POSS according to the present invention is introduced into the side chain of one main chain to enhance mechanical property, thermal stability, heat resistance and luminescence efficiency. Such a side-chain-tethered POSS polymer may be applied to various polymer photoelectric devices, such as electroluminescence LED plate display, plate luminescence source, solar cell, plastic IC or sensor, and so on.
Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that other modifications and variation can be made without departing the spirit and scope of the invention as hereafter claimed.
Claims
1. An electroluminescence polymer material comprising a polymer main chain and at least a side chain linked on said polymer main chain, wherein said side chain comprises an inorganic compound with a steric hindrance.
2. An electroluminescence polymer material according to claim 1, wherein said polymer main chain comprises a copolymer.
3. An electroluminescence polymer material according to claim 2, wherein said copolymer comprises an incorporation of poly (1,4-phenylene vinylene) (PPV) and conjugated polymer (poly(2-methoxy-5-[2-ethylhexyloxy]-1,4-phenylenevinylene) (MEHPPV).
4. An electroluminescence polymer material according to claim 1, wherein said side chain comprises a polyhedral oligomeric silsesquioxane (POSS).
5. An electroluminescence polymer material according to claim 4, wherein said polyhedral oligomeric silsesquioxane is linked to said polymer main chain containing poly(1,4-phenylene vinylene).
6. A red luminescence polymer material comprising a polymer main chain and at least a side chain linked on said polymer main chain, wherein said side chain comprises polyhedral oligomeric silsesquioxane (POSS).
7. A red luminescence polymer material according to claim 6, wherein said polymer main chain comprises an incorporation of poly(1,4-phenylene vinylene) (PPV) and conjugated polymer (poly(2-methoxy-5-[2-ethylhexyloxy]-1,4-phenylenevinylene) (MEHPPV).
8. A red luminescence polymer material according to claim 6, wherein said polyhedral oligomeric silsesquioxane is linked onto said poly(1,4-phenylene vinylene).
Type: Application
Filed: Oct 26, 2006
Publication Date: Feb 28, 2008
Applicant:
Inventors: Kung-Hwa Wei (Hsinchu), Chia-Hung Chou (Hsinchu)
Application Number: 11/586,652
International Classification: C08F 8/00 (20060101);